How stressful is medical training? So bad that in a class that encouraged medical students to express their feelings by drawing comics, nearly half of them depicted their supervisors as monsters, researchers say.

Students imagined the workplace as dank dungeons, represented supervising physicians as fiendish, foul-mouthed monsters, and themselves as sleep-deprived zombies walking through barren post-apocalyptic landscapes, the study authors, Daniel R. George and Dr. Michael Green, wrote Tuesday in JAMA, the journal of the American Medical Association. They teach the Comics in Medicine class at Penn State College of Medicine.

In one particularly harrowing image, a student "depicted his supervising physician screaming at the medical team, causing one intern to urinate herself moments before having her head bitten off for possessing too little information about a patient," the authors wrote.

While the article referred to only the 66 fourth-year students who have taken the humanities class since 2009, a much larger study in the same special annual medical education issue of JAMA found that nearly one-third of more than 17,000 medical residents in 31 studies screened positive for depression or depressive symptoms.

That study, by researchers from several leading medical schools, including Harvard, Yale and Cambridge in England, adds to a body of work showing that the stress of training can cause depression.

Over a lifetime the depression rate for doctors is similar to the general population, about 10 to 13 percent in male physicians and 20 percent in females, compared with 16 percent overall. according to an editorial written by Dr. Thomas Schwenk, dean of the Unviersity of Nevada Medical School. So it looks like the number of doctors affected during their residencies is significantly higher.

And it's not just the doctors themselves who suffer — patients should worry, too. Depression in residents "has been linked to poor-quality patient care and increased medical errors," the researchers note.

The two reports demonstrate that something is wrong with the medical training system, according to Schwenk. "The profession purportedly recognizes the importance of health and wellness," he wrote, "but the value system of the current training environment makes clear to residents the unacceptability of staying home when ill, of asking for coverage when a child or parent is in need, and in expressing vulnerability in the face of overwhelming emotional and physical demands."

A big part of the problem is that medicine has long been taught by treating underlings harshly, which has been considered acceptable because a mistake could cost a patient her life.

"People treat people like they were treated," said Green, a physician and professor of internal medicine at Penn State, in an interview. " 'This is how I did it and I'm OK, so I'm going to do it to you and you'll be OK.' "

But medicine itself has changed, Schwenk said in an interview, and that compounds the problem. "My era [the 1970s] came away with very strong role models and people who were incredibly influential," he said. "Today everyone is so frantic," with patients moving in and out of hospitals faster and strict protocols for patient care. That leaves little time or space for more benevolent types of supervision and teaching for doctors in training.

Schwenk says it's time for the pendulum to swing back toward more personalized training after medical school. "There's got to be a shift back toward dedicated teaching and mentorship," he said. "We've lost that because of the craziness of the system."

Doctors who train other doctors also need to practice what they preach, he says. "We don't teach in ways that encourage wellness and good mental health and coping mechanisms."

Green says the system needs to stop the abuse of medical students and residents by professional superiors.

"There has to be a message that this is not OK and there will be consequences for treating people badly," he said.

Both doctors said they hope that bringing more visibility to the problem could help lead to needed changes. Said Green: "My hope is it's getting better because we're much more sensitized to these issues."